Manufacture of molded, binder-reinforced, airlaid fiber articles



M. O. SCHUR Nov. 15, 1938.

MANUFACTURE OF MOLDED, BINDER-REINFORCED, AIRLAID FIBER ARTICLES Filed 001:. 8. 1935 Patented Nov. 15, 1938 PATENT OFFICE- MANUFACTURE OF MOLDED, BINDER-REIN- FORCED, AIRLAID FIBER ARTICLES Milton 0. Schur, Berlin, N. 11., assignor to Brown Company, Berlin, Maine N. 11., a corporation of Application October 8, 1935, Serial No. 44,015

3 Claim.

This invention relates to the manufacture of molded, binder-reinforced, airlaid fiber articles. While not restricted thereto, it relates more particularly to the manufacture of seamless hats ii simulating true felt hats in such qualities as pliancy, feel, and appearance.

In accordance with the present invention, hat

shapes or other molded articles are formed by depositing fibers in substantially individualized l0 condition from suspension in air or equivalent gaseous medium onto a wire cloth or other suitable foraminous mold to form what may be termed an airlaid fibrous body, the mold preferably being under suction to promote an interfelting or matting of the fibers into a coherent body. Such practice is advantageous in that it lends itself to satisfactory performance with inexpensive, comparatively short-fibered raw material, such as Wood pulp, as well as with cotton, wool, hair, asbestos, or other fibrous material of vegetable, animal or mineral origin, provided that thefibrous material is initially disintegrated into substantially individualized fiber units which can be suspended in an air current and carried by such current onto the mold so as to deposit a substantially uniformly textured, coherent body thereon. As the fibers are being delivered to the mold, they may be superficially coated, as by spraying, with binder so that the deposited or molded fibers will-be directly integrated into a binder-reinforced article; or the premolded fibrous article may, preferably after being compacted or consolidated to the desired thickness and strength, he impregnated with the desired toughening or reinforcing binder. In the case of hats, the binder-reinforced hat shape is then finished on either or both faces with fiber flock to resemble in feel and appearance a true felt hat. 40 I shall now deal specifically with hat-making practiced in accordance with the present invention, as hats may be produced thereby' at very low cost and yet, because of the softness of their airlaid fiber base even after compacting, be made.

45 ,to simulate true felt hats or suede articles in development of hydrated or gelatinized celluloses that act to stiffen the resulting molded fibrous structure.

With the foregoing and other features and objects in view, I shall now describe my invention in greater detail with particular reference to the accompanying drawing, wherein,--

Figure 1 shows somewhat diagrammatically the molding of a hat shape in accordance with my invention.

Figures 2 and'3 illustrate the step of compacting the molded shape.

Figure 4 depicts the resulting shape.

As shown in Figure 1, the molding apparatus may include a suction box l0 over which a hollow hat moldll may be removably placed with its marginal portion I2 resting on a flange l3 constituting the upper end portion of the walls of the box. That hat mold may be formed from wire cloth of fine mesh such as that serving as the forming wire of a Fourdrinier papermaking machine; or it may be made of any other suitable foraminous material on which fiber can be retained or deposited from suspension in air. Leading from the suction box I0 is a pipe I communicating with a suction chamber or pump (not shown) serving to maintain the interior or hollow of the mold under the desired suction during the hat-molding operation.

During the molding operation, the mold may, as shown, be covered and enclosed from the atmosphere by a hood l5 fixed to the discharge end of a fiber-delivering conduit 16. The lower end portion ll of the hood may be flanged and rest on the .marginal portion I! 'of the mold.

Within the hood i5 is preferably provided a coarsely foraminous or perforated gauge member l8 of a shape corresponding to the hat mold but spaced therefrom a predetermined distance so as to permit fiber to deposit on the mold to a fixed substantially uniform thickness or gauge during the molding operation. The hood l5 and conduit l6 are designed to be raised from the mold by suitable means (not shown) after the molding operation has been completed to the dotted line position so as to permit another mold to be placed over the suction box.

The conduit I6 is progressively supplied during the molding operation with fiber suspended in air as substantially individualized fiber units from a suitable source of supply (not shown), for instance, from a hammermill or other suitable disintegrator whose exit is equipped with a fan or blower exhausting directly into the conduit I6. Thus, wood pulp or other suitable fibrous material or fibrous mixture, as hereinbefore mentioned, may be fed into a hammermill or other disintegrator capable of cleaving apart the fiber units so that, as they are being discharged from the dlslntegrator, they can be carried away in a blast of air created at the discharge of the disintegrator and delivered while thus carried or suspended in air to the mold. As the fibers are descending the conduit l5, they may be sprayed, as from a spray nozzle IS, with suitable binder so that as they are being deposited under suction onto the mold, they may be bonded as well as felted together into a coherent hat body or shape. The openings or perforations in the gauge member is should, of course, be suificiently large to permit the fiber to pass readily therethrough and be deposited with the desired uniformity on the mold Ii.

After a molding operation has been completed and the hood i5 and conduit Hi have been raised from the mold to the dotted line position shown in Figure 1, the hollow mold together with the hat shape S carried thereby is removed from the suction box so that the shape may be subjected to the desired compacting or consolidating action while still on the mold. To this end, the mold may be placed on a suitable solid base or supporting form 30, which as shown in Figure 2, has a configuration corresponding essentially to the internal configuration of the mold and is designed to keep the mold and the hat shape carried thereby from distortion when a compacting or compressing form 3| of the appropriate configuration, also shown in Figure 2, is brought down to bear with sufficient pressure on the hat shape to reduce it to the desired thickness preparatory to impregnation, if necessary, and surfacing or finishing with fiber flock. As appears in Figure 3, the hat shape S may in this way be compacted to a small fraction, say, to of the thickness possessed thereby before its compaction. In this connection, it might be observed that the airlaid fibrous body is apt to be fluffy and fragile as directly deposited, particularly when no binder is used in integrating or unifying the fibers into the body. Accordingly, the step of compacting the hat shape makes possible subsequent handling and treatment thereof without need of keeping the shape on the mold even when binder is omitted in the formation of the hat shape.

Once the hat shape has been compacted so that it can be handled and treated without in- Jury in the absence of the mold on which it is formed, it may be removed from the mold for further treatment. In the event that the shape is formed without binder, it is impregnated with suitable binder, for instance, such binders as rubber latex, artificial aqueous rubber dispersions, organic solvent solutions of rubber, aqueous solutions of'glue, viscose, etc. Such binders may also be sprayed onto the fibers as they are being deposited on the hat mold, as hereinbefore indicated. Assuming that impregnation of the premolded and compacted hat shape is being effected, such shape may be sprayed or otherwise treated on either or both its faces with the rubber latex or other binder to effect a substantial impregnation of its body, or, if desired, a substantially complete impregnation thereof.

Irrespective of whether the hat shape is formed in the presence of binder or whether binder is subsequently infused thereinto, it is then preferably surfaced with fiber flock so as to simulate true felt or suede in its appearance and feel. If the hat is molded in the presence of binder, it is necessary to apply additional binder, such as rubber latex, glue, nitrocellulose cement, etc., as by spraying on the surface of the hat and then to shower fiber flock on the sticky hat surface, for instance, as the hat is supported on a suitable form or block, with rotary or other appropriate movement of the form, if desired, to ensure substantially uniform flocking of the hat surface with fiber. At least the outer surface of the hat is preferably thus finished with fiber flock; and it is usually desirable to turn the hat inside out on the supporting form after its outer surface has been finished and. to finish the nowouter surface in the same way as the previouslyouter surface. In those instances when the molded hat shape undergoes an after-impregnation with rubber latex or other suitable binder,

as by spraying the binder on the shape while supported by a form or block, sufficient binder may be applied not only to effect impregnation of the body of the shape to the desired degree but to develop an adhesive coating on its surface which is showered with fiber fiock and then permitted to dry or set. Thereupon, if desired, the inside surface of the hat may be treated with binder and also flock, as hereinbefore described. Of course, fiber flock of any suitable color or sheen may be employed; and, if desired, flock of one or more colors may be distributed locally on the hat surface to produce highly ornamental effects, the binder for the fiock and/or the flock being applied, for instance, through suitable stencils in producing such effects.

The fiock or finished hat may be given a final "blocking" or shaping as is customary in hat manufacture; and it may be provided with the usual accessory hat elements, such as a lining, sweat band, etc., and the usual hat ornaments, such as an outer band or ribbon, buttons, feathers, buckles, etc.

Various proportions of binder may serve as the reinforcing or toughening element in the hat shape. Thus, the hat shape may contain from about 5 to of rubber, or from about 8 to 40% of glue, or from about to 5% of cellulose regenerated from viscose, based on the dry weight of fiber in the hat shape. In the case of all of these binders and especially in the case of glue and viscose, it is desirable to introduce a suitable softening or plasticizing agent into the hat shape in order to neutralize or offset such undesirable stiffening action of the shape as may come from the binder. Thus, hat shapes impregnated with dry rubber latex solids may to advantage contain about 5 to 25% of glycerine, based on latex solids; those impregnated with glue, about 75 to 200% of glycerine, based on glue solids; and those impregnated with about to 5% cellulose regenerated from viscose, about 5 to 30% of glycerine, based on the dry weight of fiber. Other softening agents, such as ethylene glycol or other homologues of glycerine, glucose or other invert sugars, Nulmoline, and the like might be employed in lieu of glycerine. The glycerine or other softening agent may be introduced directly into such impregnants as rubber latex, glue solution, and viscose, with which they are compatible; or they may be applied to the binder-impregnated hat shape either generally or locally, as in the form of aqueous solutions. So, too, such stiffening agents as water-glass, starch paste, etc., may be added to the hat shape amass? ers such as rubber latex and glue, rubber latex and viscose, v and rubber latex, glue and viscose may be admixed to develop the proper degree of stifiness in thehat. In this connection,- it might be noted that the addition of glue and/or viscose to a rubber latex binder has the effect of increasing the stiffness of the hat shape impregnated with the binder. As in the case of the softening agent, the stiffening agent may be infused into the binder-impregnated hat shape. as in the form of an aqueous solution; and such infusion may be had generally or' locally, for instance, only at the brim portion of the hat, whereat greater stiffness is generally desired than at the crown portion.

While the thickness of the hat body or structure prior to surfacing it with fiber flock is subject to variation, it is generally the case that the thickness desired ranges from about 20 to 60 mils, as at such thickness it can be finished with fiber flock to produce a final hat structure or body whose thickness is comparable to that of suede or felt in a true felt h t. However, as previously indicated, the hat shape asinitially molded may be of much greater thickness, say, of two or five times such thickness, and compacted or consolidated to such thickness preparatory tothe finishing or surfacing operation with fiber flock.

I claim:-

1. A method of making a molded fibrous article, which comprises depositing short-fibered raw material of the nature of wood pulp as substantially individualized fiber units from suspension in air onto a hollow foraminous mold under internal suction to form on said mold said article as a, molded fibrous structure of much greater thickness than that desired in the finished structure; placing the hollow mold and the molded fibrous structure carried thereby on a supporting form whose configuration corresponds essentially to the internal configuration of said mold; and, while the hollow mold carrying said molded fibrous structure is thus placed on said supporting enable it to be removed from said mold and handled without injury.

2. A method of making a molded fibrous article, which comprises depositing shortfibered raw material of the nature of wood pulp as substantially individualized fiber units from suspension in air onto a hollow foraminous mold under internal suction to form on said mold said article as a fiufi'y and fragile molded fibrous structure of a thickness at least about twice that desired in the finished-structure; placing the hollow mold and the molded fibrous structure carried thereby on a supporting form whose configuration corresponds essentially to the internal configuration of said mold; and, while the hollow mold carrying said molded fibrous structure is thus placed on said supporting form, bringing a compressing form of approprlate configuration to bear with sumcient pressure on said structure to compress it to not more than about one-half its thickness and thereby to impart thereto sufilcient tenacity to enable it to be removed from said mold and handled without injury.

3. A method of making a molded fibrous article, which comprises depositing short-fibered raw ma terial of the nature of wood pulp as substantially individualized fiber units from suspension in air onto a hollow foraminous mold under internal suction to form on said mold said article as a fiufiy and fragile molded fibrous structure of a thickness at least about twice that desired in the finished structure; placing the hollowmold and the molded fibrous structure carried thereby on a supporting form whose configuration corresponds essentially to the internal configuration of said mold; while the hollow mold carrying said molded fibrous structure is thus placed on said supporting form, bringing a compressing form of appropriate configuration to bear with sufiicient pressure on said structure to compress it to not more than about one-half its thickness and thereby to impart theretosufilcient tenacity to enable it to be removed from said moldand handled without injury; impregnating the compressed, molded, fibrous structure with binder to bond together its fibers; and surfacing the resulting impregnated, compressed, molded, fibrous structure with fiber flock.

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